The present invention relates to a pin plug comprising a plug cover made of a substantially cylindrical body of a metal and having a front end divided into several branches, a pin made of a substantially tubular body of a metal which is arranged inside of said plug cover coaxially therewith, two conductors of an electric wire being connected to said plug cover and pin, respectively and a molded body of electrically insulating synthetic resin which covers the rear ends of the plug cover and pin and that end of the electric wire which is connected to the plug cover and pin.
Such a pin plug has been widely used for interconnecting in a simple and stable manner various electronic devices such as a radio receiver, a television receiver, a disc player, a tape recorder, an audio amplifier, etc.
In a known pin plug which has been commercially available a plug cover and a pin are fixed in position by means of an electrically insulating plate prior to molding. That is to say in a first step of manufacturing process the pin of a metal tube is fixed to the insulating plate by means of clamping. Then the insulating plate is fixed in the plug cover by clamping. In this manner the plug cover and pin are fixed in position with the aid of the insulating plate. Next to the pin and plug cover are connected two conductors of an electric wire by means of soldering. Finally the assembly is molded with synthetic resin. Such a known pin plug requires at least one insulating plate in addition to the plug cover and pin, so that manufacturing process becomes complicated. Particularly the process for assembling the plug cover and pin with the aid of the insulating plate is rather complicated. Thus the known pin plug could not be manufactured automatically. Moreover since the insulating plate exposes to the outside, wet-proof of the insulating resistance is liable to be deteriorated. Thus attention should be paid in selecting material of the insulating plate.
The present invention has for its object to provide a pin plug of a novel construction which does not require the insulating plate, so that it can be manufactured in a very simple and inexpensive manner and also has good electrical and mechanical properties.
It is another object of the invention to provide a pin plug in which the plug cover can be firmly coupled with the molding body of synthetic resin.
It is another object of the invention to provide a pin plug which is particularly suitable to be manufactured in a substantially automatic manner.
It is still another object of the invention to provide a method for manufacturing a pin plug in a mass production manner.